Japanese Patent No. 3,279,913 discloses a method of detecting face feature points. According to this method, feature point candidates are detected by a separability filter, and a set of feature points is selected on the basis of an arrangement of feature points when these feature point candidates are combined with one another, and template matching of a partial area of a face is carried out.
The estimation of the feature point arrangement in the above-described related art is carried out two-dimensionally, and thus it has been difficult to deal with variation of a face direction or the like.